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Check that we really have a boot0 mbr before treating it as one.

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Suggested by: peter

Also add a few comments.
This commit is contained in:
Robert Nordier 1999-06-22 18:57:49 +00:00
parent 6dcd4819f1
commit d1306cd89d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=48113
1 changed files with 47 additions and 4 deletions
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51
usr.sbin/boot0cfg/boot0cfg.c
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@ -26,7 +26,7 @@
#ifndef lint
static const char rcsid[] =
"$Id: boot0cfg.c,v 1.4 1999/06/19 21:44:43 rnordier Exp $";
"$Id: boot0cfg.c,v 1.5 1999/06/21 14:40:59 rnordier Exp $";
#endif /* not lint */
#include <sys/param.h>
@ -72,11 +72,15 @@ static const char fmt0[] = "# flag start chs type"
static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x"
" %4u:%3u:%2u %10u %10u\n";
static int boot0bs(const u_int8_t *);
static void stropt(const char *, int *, int *);
static char *mkrdev(const char *);
static int argtoi(const char *, int, int, int);
static void usage(void);
/*
* Boot manager installation/configuration utility.
*/
int
main(int argc, char *argv[])
{
@ -139,6 +143,8 @@ main(int argc, char *argv[])
errx(1, "%s: short read", disk);
if (cv2(buf + OFF_MAGIC) != 0xaa55)
errx(1, "%s: bad magic", disk);
if (!B_flag && !boot0bs(buf))
errx(1, "%s: unknown or incompatible boot code", disk);
if (fpath) {
if ((fd1 = open(fpath, O_WRONLY | O_CREAT | O_TRUNC,
0666)) == -1 ||
@ -154,8 +160,8 @@ main(int argc, char *argv[])
err(1, "%s", bpath);
if (n != MBRSIZE)
errx(1, "%s: short read", bpath);
if (cv2(buf + OFF_MAGIC) != 0xaa55)
errx(1, "%s: bad magic", bpath);
if (!boot0bs(buf))
errx(1, "%s: unknown or incompatible boot code", bpath);
memcpy(buf + OFF_PTBL, part, sizeof(part));
}
if (d_arg != -1)
@ -209,6 +215,34 @@ main(int argc, char *argv[])
return 0;
}
/*
* Decide if we have valid boot0 boot code by looking for
* characteristic byte sequences at fixed offsets.
*/
static int
boot0bs(const u_int8_t *bs)
{
static u_int8_t id0[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a};
static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
static struct {
unsigned off;
unsigned len;
u_int8_t *key;
} ident[2] = {
{0x1c, sizeof(id0), id0},
{0x1b2, sizeof(id1), id1}
};
int i;
for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++)
if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len))
return 0;
return 1;
};
/*
* Adjust "and" and "or" masks for a -o option argument.
*/
static void
stropt(const char *arg, int *xa, int *xo)
{
@ -237,6 +271,9 @@ stropt(const char *arg, int *xa, int *xo)
free(s);
}
/*
* Produce a device path for a "canonical" name, where appropriate.
*/
static char *
mkrdev(const char *fname)
{
@ -244,7 +281,7 @@ mkrdev(const char *fname)
struct stat sb;
char *s;
s = (char *) fname;
s = (char *)fname;
if (!strchr(fname, '/')) {
snprintf(buf, sizeof(buf), "%sr%s", _PATH_DEV, fname);
if (stat(buf, &sb))
@ -255,6 +292,9 @@ mkrdev(const char *fname)
return s;
}
/*
* Convert and check an option argument.
*/
static int
argtoi(const char *arg, int lo, int hi, int opt)
{
@ -268,6 +308,9 @@ argtoi(const char *arg, int lo, int hi, int opt)
return x;
}
/*
* Display usage information.
*/
static void
usage(void)
{